Thomas Fogarty, M.D. will turn 65 in December. The chief medical officer of Concentra, the nation’s largest operator of urgent-care and occupational health clinics, shrugs off the milestone.

“As long as I am having fun, I’m going to keep doing what I’m doing,” he says.

Fogarty was one of three founders of Addison-based Concentra. He was a Houston-based industrial engineer when he decided to go to medical school at Texas Tech University School of Medicine. He spent his fourth year of medical school in his hometown of Amarillo, where Concentra was born in 1970, when he and two other physicians opened an occupational health clinic.

Fogarty migrated to Dallas-Fort Worth when the trio opened a second clinic in Garland in 1985. By the end of that decade, Concentra had a half dozen locations.

The company, which was acquired by Humana in 2010 for $790 million, now dominates its niche. Fogarty is responsible for overseeing the medical practice of more than 1,200 clinicians, who primarily treat injuries and illnesses, do drug testing, and perform physical examinations.

Company officials estimate they treat about 15 percent of U.S. work-related injuries. Its widespread clinic footprint means Concentra is within a 15-20 minute drive for about 40 percent of the U.S. work force.

In response to employers’ concerns about rising group health costs, the company has expanded into other employer-focused business lines, including primary, preventive, and environmental health and safety services. It also operates more than 270 employer-worksite medical clinics, including one at Dallas City Hall.

In 2007, Concentra expanded beyond occupational health to include urgent care and health and wellness programs. Fogarty declined to reveal the company’s revenue, but did say that he expects to add another 100 clinic locations within the next five years, as well as more onsite occupational centers.

For 15 years, Fogarty has brought an engineer’s sensibility to tracking the performance of his clinicians, using evidence-based medicine long before it became healthcare’s mantra. He serves as an officer of the Concentra Occupational Health Institute, established in 2000.Dan Thomas, president and CEO of Irving-based Provista, says, “Dr. Fogarty’s fingerprints are all over Concentra. He has been its conscience for many years—always placing the patient first and never compromising clinical care and best practices.”

Despite being a top executive at a major, fast-growing company, Fogarty continues to comport himself as a humble country doctor—and remains unimpressed: “I don’t view my personal accomplishments as all that great.”